Although NIV is a simple and useful method, considerable variation in its use across countries, regions and hospitals may be noted. The patient should be evaluated according to subjective response (respiratory distress, consciousness, problems related to mask and airflow), physiological responses (respiration rate, respiratory effort, air leakage) and patient-ventilator compliance (gas exchange, pulse oximetry, arterial blood gases). Normalization in respiration rate within 1 or 2 hours after initiation of treatment is one of the most important markers for recovery. The goal is to maintain respiration rate between 20 and 30 breaths/ minute. Reduction in intercostal and supraclavicular retractions, paradoxical respiration and sympathetic activity indicate success of treatment. Arterial blood gases are measured within first 2 hours in order to assess pH and CO 2 ; and as needed thereafter. In general, NIV is assessed by arterial blood gases, hemodynamic parameters and several laboratory tests. There is limited number of studies in NIV. Here, we aimed to assess radiological implications of gas distribution within lung tissue during NIV therapy.